This may have been answered somewhere before, but I cant seem to find it, and I'm NEED to know . I have 142 pets on my main, I have 8 more pets that I got on an alt that I never was able to get on my main, read Ice Chip =o), now when MOP comes out and pets go account wide, I should have 151 pets, will I still get the acheivement for the 150 pets and be able to get the celestial dragon? Or will I have to kill myself trying to get thouse last few before then?

Yes, you should get your Celestial Dragon. Although it might not be mailed to you like normal. Instead, it might be automatically added to your Pet Journal. So double-check your Pet Journal on the 28th (when the update comes out).